1. Field of the Invention
The present invention relates in general to digital data processing and in particular to circuits, systems, and methods for processing multiple data streams.
2. Description of the Related Art
The ability to process audio information has become increasingly important in the personal computer (PC) environment. Among other things, audio is important in many multimedia applications, such as gaming and telecommunications. Audio functionality is typically available on most conventional PCs, either in the form of an add-on audio board or as a standard feature provided on the motherboard itself. In fact, PC users increasingly expect not only audio functionality but high quality sound capability.
Although PC manufacturers are sensitive to meeting their customers' demands for enhanced audio capability, they must also be aware of the tight price margins imposed on their products. In order to balance these competing interests, system designers must strive to provide as much audio functionality as possible while minimizing the number of components required to perform a given function. From the functionality point of view, a state-of-the-art digital audio processing subsystem should provide for such diverse processing techniques as wavetable synthesis, 3-D audio, and sample rate conversion. Sound Blaster compatibility and compatibility with future systems not relying on Sound Blaster technology must also be considered. Further, such a subsystem should be capable of integration on a PC system motherboard through the now widely used PCI bus with its higher bandwidth. From a cost and efficiency point of view, a single chip solution would be optimal. Additionally, the next generation of games will require the processing of simultaneous streams of audio data and thus any system should address the multiple streaming requirements of game designers.
Thus, the need has arisen for an audio processor solution for simultaneously processing multiple streams of digital audio information. Among other things, there is a need for an audio processor that provides for wavetable synthesis operations, including general MIDI wavetable synthesis, and voice channel effects like reverb and chorus. Further, there is a need for such a device to provide 3-D audio processing and direct sound support. Additionally, there is a need for such a device to perform processing functions, such as Dolby.TM. AC-3 audio decoding. There is also a need for such a solution to account for such factors as varying potential system configurations. For example, there is a need for such a device to interface directly with a codec or through an additional audio processing device, such as an audio motherboard. There is also a need for such a device to interface with a PCI bus.